Add some helpful messagesw and fix bug

app.py

@@ -57,7 +57,7 @@ def read_data(output_file: str) -> pd.DataFrame:
         st.session_state.data = {}
 
     if "all_files" not in st.session_state:
-        st.session_state.all_files = []
+        st.session_state.all_files = ["files/bottleneck.json"]
         # User will select from these files to do simulations
 
     tab = init_sidebar()
@@ -144,15 +144,15 @@ def read_data(output_file: str) -> pd.DataFrame:
 
             with st.spinner("Simulating ..."):
                 if fps and time_step:
-                    simulation.main(
+                    evac_time = simulation.main(
                         number_agents,
                         fps,
                         time_step,
                         simulation_time,
                         data,
                         Path(OUTPUT_FILE),
                     )
-            msg.code("Finished simulation")
+            msg.code(f"Finished simulation. Evac time {evac_time} s")
             st.empty()
         output_path = Path(OUTPUT_FILE)
         if Path("values.txt").exists():

simulation.py

@@ -251,7 +251,7 @@ def main(
     logging.info(f"Simulation completed after {simulation.iteration_count()} iterations")
     logging.info(f"simulation time: {simulation.iteration_count()*_time_step} [s]")
     # logging.info(f"Trajectory: {_trajectory_path}")
-
+    return  simulation.iteration_count()*_time_step
 
 if __name__ == "__main__":
     init_logger()